GB Line Engraved Penny Black SG1 Plate 5 on envelope addressed to The Pay Office, Whitehall. More details below.(LPS28)

GB Line Engraved SG1 Plate 5 on envelope addressed to The Pay Office, Whitehall. The stamp caused some serious discussions. This from an expert: "penny black from plate 5 that's the easy bit. plate 5 comes in 5 states, but L-H shows as not been repaired in my books, BUT this copy shows all the signs of being re-entered and the lines on the head strengthened, but the check letters and stars in states 2 and 3 should be weakened, but these are not, they look like states 4 or 5, but those repairs were not done until Jan 1841 and this stamp was used in 1840 ???? I have no explanation. yet. 

Follow up: "That plate 5 L-H only explanation I can think of is that it is state 1 a very early copy while setting up the plate and the paper moved while printing making it look like a re entry. L-H does not show as having any repairs."

You decide!